Functional and numerical responses of the predatory bug Macrolophus caliginosus Wagner fed on different densities of eggs of the greenhouse whitefly, Trialeurodes vaporariorum ABDUL-JALIL SALEM HAMDAN Department of Plant Production and Protection, Faculty of Agriculture, Hebron University, Hebron P.O. Box 40, Palestine Abstract Laboratory experiments under standard conditions (25°C, 50-75% relative humidity, 16:8 L:D) were conducted to determine the functional and numerical responses of the adult female of Macrolophus caliginosus to different densities of the greenhouse whitefly on tobacco leaf discs. The results showed that the functional response of M. caliginosus was density-dependent with regard to the consumption of Trialeurodes vaporariorum eggs at different prey densities, up to 300 T. vaporariorum eggs/arena/day. This response fitted the type III functional response. The numerical response of M. caliginosus was positively related to prey density, with more oocytes per female, a higher age-specific fecundity and higher intrinsic rate of increase at high prey densities than medium or low prey densities.   < back .